Summary: The authors develop and implement a method for measuring the frequency of changes in power among distinct leaders and ideologically distinct parties that is comparable across political systems. The authors find that more frequent alternation in power is associated with the emergence of better governance in post communist countries. The results are consistent with the hypothesis that firms seek durable protection from the state, which implies that expected political alternation is relevant to the decision whether to invest in influence with the governing party or, alternatively, to demand institutions that apply predictable rules, with equality of treatment, regardless of the party in power.